Shock sensitive latch-releasing device



April 23, 1964 H. E. SCHLEICHER 3,130,590

SHOCK SENSITIVE LATCH-RELEASING DEVICE Filed April 19, 1961 66 H 1 4/ qa50 2 35 /a I 5/ ZYII-I'IIII i C) 32 I;

m /4 M V //7l/6/7 for F/ 4 H5 5 Ham/d E. Sch/ether By his affomeys #mwzUnited States Patent ()fiice 3,130,590 Patented Apr. 28, 1964 3,130,590SHQCK SENSITIVE LATCH-RELEASING DEVICE Harold E. Schleicher, WestHartford, Conn., assignor to The Arrow-Hart & Hegeman Electric Company,Hartford, Comm, a corporation of Connecticut Filed Apr. 19, 1961, Ser.No. 104,117 19 Claims. (Cl. 74-2) This invention relates to a devicewhich is sensitive to shocks of predetermined force values and, moreparticularly, to provision in such a device for releasing a latch onlywhen said predetermined shock forces are reached or exceeded.

Particularly in recent years, devices have been developed which are heldclosed or open or in some predetermined condition by latches or the likeso as to be able to withstand severe shocks of great force valueswithout their condition changing. It is desirable for such devices toretain such characteristics, but under some conditions it is alsodesirable that such devices be unlatched or released when subjected tosome shock force value less than that which the device would normallywithstand.

Therefore, one object of the invention is to provide a latch-releasingdevice which is sensitive to shock forces of predetermined value andwhich will become effective when such value is reached or exceeded.

Another object is to provide a device of the aforesaid type which isbalanced and counterweighted in such a way as to respond equally to ashock force applied regardless of the direction of force action.

Another object is to provide for actuation of a device of the aforesaidtype either manually at the device or under eletcromagnetic control froma remote point.

Another object is to provide a device of the aforesaid type which issimple in structure and made of durable readily available materials andeasily manufactured parts, and which may be assembled inexpensively andtaken apart for inspection or repair easily and in which duplicate partsare used to maximum advantage, thus to keep to a minimum the cost oftooling and the cost of manufacture, without sacrifice of reliability.

Other objects and advantages of the invention will appear as theinvention is described in connection with the accompanying drawing.

In the drawing:

FIG. 1 is a transverse section view taken along line 11 of FIG. 2.

FIG. 2 is a plan view, partly broken away at the right end, of thedevice shown in FIG. 1.

FIG. 3 is an end elevation view of the device shown in FIG. 1.

FIG. 4 is an enlarged detail section view of one of the outsidecounterweights showing the means for securing the cable thereto.

FIG. 5 is an enlarged detail section view of the same \outsidecounterweight as in FIG. 4, but with the section taken at right anglesto the section of FIG. 4.

Referring to the drawing, the mechanism is conveniently mounted betweenoppositely facing similar molded blocks,

preferably of nylon or other light-weight material having a smoothslippery surface which is in effect self-lubricating in the sense thatit requires no additive for lubrication. The blocks are provided withrecesses to receive the fixed and moving parts of the mechanism.

Extending through a small passage in the blocks is a stainless steelflexible wire or cable 14 having fastened on each end a truncatedconical counterweight 16, 18 whose larger ends lie against the outeropposite end surfaces of the blocks 10, 12. The cable 14 is preferablyof stainless steel or other similar material which will not stretch orbe permanently lengthened when subjected to the stresses to which thedevice is designed to respond. Also preferably, the small passage andthe recesses for other parts between the blocks are molded so that onehalf of each of the parts (as hereinafter more particularly described)will be located in each of the blocks. The molded blocks may thus beidentical.

Tension is applied to the cable at its middle by a coiled compressionspring 20 located in a molded bore 21 transverse to the cable passage.The spring is anchored or presses at one end against a peripheralshoulder on an adjustment screw 22 threaded through the transverseportion of a U-shaped bracket 24 having its ends bent oppositely. Onehalf of the bracket fits into a recess shaped to fit it in the block 10while the other half fits into a like complementary recess in the block12.

By adjusing the position of the screw, the pressure of the spring 2% maybe adjusted. The opposite end of the spring presses against a latchedlug 26 in the opposite end of the transverse passage 21. Formed in theinner end of the latched lug is a diametrical slot extendinglongitudinally toward the middle of the lug. In the slot is located acentral pulley 30 made of nylon or other lightweight material,preferably a plastic material having similar characteristics to nylon,although a light-weight metal pulley can be used.

The pulley 30 is mounted rotatably on an axle pin or thin shaft 31extending transversely through the center of the pulley with its endsmounted in the latched lug.

The cable 14 is trained around the center pulley 30 and also aroundsimilar nylon pulleys 32 and 34 on opposite sides of the spring passage21 and located so that the portions of the cable between the pulleys 32and 34 and counterweights 16 and 18 are in alignment and also lie in theplane of the abutting faces of the blocks 10 and 12. For convenience,these aligned portions will be referred to as the cable axis.

Thus, the spring applies tension to the cable 14 by means of the centerpulley 3t). Simultaneously, it presses the latched lug 26 into positionto latch and hold a biased member 218.

For the purpose of illustration, the latched member 28 is shown as adisc on a shaft 29 biased by means (not shown) in clockwise direction(referring to FIG. 1) such as the shaft on a rotary actuator, such as inmy Patent 2,540,294 issued February 6, 1951. understood that theinvention is not limited in any respect to such use, which is mentionedmerely as exemplative, but the invention may be used in connection witha rectilinearly movable latched member or any other biased latchedmember.

The cable passes freely through truncated conical inside counterweights36 and 38 which are seated in aligned truncated conical recesses inopposite ends of the blocks 10 and 12.

With the foregoing structure in mind, it can be seen that pressure, suchas might be caused by a sudden shock or a shock wave, exerted on theoutside counterweight 18 in any direction whatsoever, except parallel tothe cable axis, will have a component of force perpendicular to thecable axis tending to move the counterweight 18 laterally.

Considering the force concentrated on the center of gravity of theoutside counterweight 18, the weight will be tilted about its edgeupwardly or downwardly, as shown in dotted lines in FIG. 1, afterreaching the limit of a very limited amount of sliding motion upon thesurface of blocks 10 and 12. This will pull the cable 14, shortening theportion around the central pulley 30 and moving it and the latch contrathe force of the spring 20. This will disengage the latched lug 26 fromthe latched member 28, releasing the latter when the force issufficiently great.

It should be A like condition will obtain with respect to the outsidecounterweight 16.

When the forces act perpendicularly to the axis of the cable and theoutside counterweights 16 and 18, an equal tendency of both thosecounterweights to move or tilt will occur. As the force angle changes(as for example counterclockwise in FIG. 1), the components of force onthe counterweight 18 parallel to the cable away from the blocks and 12will increase, but the component of force perpendicular to the cableaxis will decrease. But even though the tendency to tilt may lessen, aforce acting to move the weight directly away from the blocks willbecome effective and will increase at the same time as the angle offorce increases. Thus, the tendency to shorten the portion of the cableadjacent the latched lug will continue to be exerted but in a differentway.

When the force is due to a shock, the forces acting on both the outsidecounterweights 16 and 18 will be parallel, but the components of theforce acting on one weight, such as 18, tending to move that weight awayfrom the blocks will at the same time tend to move the weight 16 towardthe block, but the components acting perpendicular to the axis will bethe same in each case and will tend to tilt both the outside weights.However, the likelihood of the weight 16 tilting will be much less inview of the fact that one of the components, namely that parallel to theaxis, acting upon the weight 16 in such a situation will not exert anytendency to tilt the weight.

Assuming the force to be exerted on the weight 16 at an angle of saythere would be less tendency of the latch to be released than if theforce acted at 90 to the axis because one horizontal component of the 45force would become a nullity due to acting directly against the blocks10 and 12. Therefore, to compenate for this loss, the insidecounterweights 36 and 38 are provided adjacent the bases of thecounterweights 16 and 18, respectively.

Since the inside counterweights 36 and 38 are loose on the cable 14, thesame force which acts upon the outside counterweights 16 and 18 at a 45angle will also act on the inside counterweights 36 and 38 at a 45angle. The component of force acting parallel to the axis of the cablewill tend to move one counterweight (assuming for example it be 38) outof its recess in the blocks and, thus, will tend to move the adjacentoutside counterweight 18 away from the blocks adding to the tendency ofthe counterweight 18 to shorten the portion of the cable around thecentral pulley 30.

When the inside counterweight 38 moves to any extent outwardly of itsrecess, it will add to the pull on the cable and if that counterweighttilts to any extent within its recess, it will bend the cable addingstill further to the tendency to shorten upon the central portionthereof and, thus, increasing the latch-releasing action.

A force acting to tend to move the counterweight 38 out of its recesswill, if similarly applied to the counterweight 36, have no effect onthe latch-releasing action because the counterweight 36 will in suchinstance be inactive and ineffective. However, if the force be rotated90 so as to be applied at a 45 angle in the opposite direction to thatfirst described, the actions just described in connection with thecounterweights 38, 18 and 16 will apply but in a similar manner, butoppositely to the counterweights 36 and 16 and to the counterweight 18.

Thus, no matter in what direction a force, such as a shock wave, actsupon the device, the tendency to unlatch the latched member 28 will bethe same.

The amount of mass of the latched lug 26 is so small with respect to thetotal mass of all of the counterweights that whether the force actedupwardly (referring to FIG. 1) at 90 to the cable axis or downwardly at90 to the case axis, the eflect would be substantially the same; and ifthe forces acted at an angle, the mass of the latched lug 26 would beeven less likely to affect the action.

Since it may be desired on some occasions to release the latch from aremote point, a pair of identical electromagnetic solenoids 40 and 50are mounted upon similar frames, designated generally by the numerals 41and 51, attached to the opposite ends of the blocks 10 and 12. Corearmatures 42 and 52, respectively, are mounted within the solenoids 40and 50 sliding within sleeves 43, 53 and are biased normally away fromthe counterweights 16 and 18 by coiled compression springs 46 and 56.The core armatures 42 and 52 may be progressively reduced in diameteralong their lengths to form steps or shoulders 43, 53 and 45, 55,respectively, which act, on the one hand, as seats for the coiledcompression springs and, on the other hand, as stops for the outwardmotion of the core armatures when the solenoids are energized.

It will be readily apparent that upon energization of the solenoids, thecore armatures will be attracted and strike against the counterweights16 and 18 accomplishing the same latch-releasing action as when a shockwave occurs. The solenoids will have no undesired effect on the actionof the device when the shock wave occurs since if the shock wave acts inthe same direction as the coil springs 46 and 56, the armatures will beinoperative for latch-releasing; and if the wave acts against the forceof the springs, the core armatures could only move outwardly, as whenenergized, and add to the desired latchtripping effect. The strength ofthe springs 46, 56 will be such as to prevent outward or tripping actionof the armatures below a predetermined shock level.

The amount of force required to actuate the device can be determined bythe strength of the latch biasing spring 20 and by the mass of thecounterweights and the degree of movement required to disengage thelatched lug 26 from the latched member 28. For example, if it weredesired that the device should not be actuated and the latch-releasingaction should not occur until a force of about five times gravityoccurred, a spring having the desired force, when adjusted, would beprovided and the counterweights would be calculated as to mass so thatany force about 5 Gs would actuate the device. Normal-ly a considerableamount of leeway is allowed so that the device might be designed foractuation of between 5 and 8 Gs or between 8 and 10 Gs and without muchdifficulty.

It is also necessary that the cable be firmly anchored in thecounterweights 16 and 18. For that purpose, a small short sleeve 60 ofcopper or other soft easily deformable metal is slipped on the end ofthe cable Within an enlargement in the outer end of the counterweight.

Transverse radial bores 61 are formed in the counterweights adjacent thesleeve 60, in which are threaded set screws 62, 64 whose ends aretruncated. The diameters of the set screws and their bores are greaterthan the diameter of the passageway for the cable through thecounterweight. Hence, at the intersection of the bores of the set screws62, 64 with the passageway for the cable there is a space avail-ableinto which the metal of the sleeve may move or flow as the set screws62, 64 are tightened and squeeze the sleeve from opposite sides. Thus,the sleeve firmly grips the cable under the stress of the force appliedby the screws 62, 64 land the sleeve is anchored against the movementaxially within the counten weight.

Manual operation may be provided by twin plungers 66 in substantialalignment with the armatures 42, 52, but on the opposite side of theweights 16 and 18 respectively. For joint operation, the plungers 66 maybe joined by a transverse connecting bar, all as shown in dot-dash linesin FIG. 1. Any suitable guiding and biasing means may be provided forthe plungers 66 to bias them away from the weights.

Many modifications within the scope of the invention will occur to thoseskilled in the art. Therefore, the invention is not limited to thespecific form and structure described.

What is claimed is:

1. In a device responsive to predetermined shock values,

a base recessed to receive fixed and movable parts of the device, aholding member mounted on said base, means biasing said member into acertain position, shock responsive means including a plurality of weightmasses movable to move said holding member from said certain position inresponse to :a predetermined shock force value irrespective of the forcedirection, and a flexible connection between said weight masses and saidholding member for moving the latter in response to said predeterminedshock force value.

2. Ina device responsive to predetermined shock values, a base recessedto receive fixed and movable parts of the device, a member mounted onsaid base and normally acting to hold another member in a predeterminedposition, shock responsive means including a plurality of weight massesmovable to cause first-mentioned member to release said other member inresponse to a predetermined shock force value irrespective of the forcedirection, and a flexible connection between said weight masses and saidholding member for moving the latter in response to said predeterminedshock force value.

3. A device as claimed in claim 2 wherein the shock responsive meansincludes equal weight masses, one being afiixed on each end of saidflexible connection.

4. A device as claimed in claim 3 having means rendering one of saidweight masses ineffective under action of a force in one directionparallel to the axis of said flexible connection.

5. A device as claimed in claim 4 wherein the shock responsive meansincludes first and second weight masses, the first masses being affixedto the opposite ends of said flexible connection, a second weight massbeing associated with each first weight mass and acting in concert withit to compensate for any ineffectiveness of the one of said first massesunder forces acting in certain directions.

6. A device as claimed in claim 5 wherein all the weight masses aresubstantially equal.

7. A device as claimed in claim 6 wherein the weight masses aredynamically symmetrical and their axes of dynamic symmetry are aligned.

8. A device as claimed in claim 7 wherein the flexible connection has adeviated portion acting on said holding member and wherein the weightmasses move under shock to alter said deviated portion and move saidholding memher.

9. A device as claimed in claim 2 wherein the flexible connection has adeviated portion acting on said holding member and wherein the shockresponsive means moves under shock to alter said deviated portion andmove said holding means.

10. A device as claimed in claim 2 wherein the shock responsive meansincludes first and second weight masses, the first masses being aflixedto the opposite ends of said flexible connection, a second weight massbeing associated with each first weight mass and acting in concert withit to compensate for any ineffectiveness of the one of said first massesunder forces acting in certain directions.

11. A device as claimed in claim 10 wherein the flexible connection hasa deviated portion acting on said holding member and wherein the shockresponsive means moves under shock to alter said deviated portion andmove said holding means.

12. A device as claimed in claim 2 wherein the shock responsive meansincludes equal Weight masses aflixed on the end of said flexibleconnection, and wherein the shock responsive means includes first andsecond weight masses, the first masses being affixed to the oppositeends of said flexible connection, a second weight mass being associatedwith each first weight mass and acting in concert with it to compensatefor any ineffectiveness of the one of said first masses under forcesacting in certain directions.

13. A device as claimed in claim 12 wherein the weight masses aredynamically symmetrical and their axes of dynamic symmetry are aligned.

14. A device as claimed in claim 2 having manually controlled meansactuatablein absence of shock force to move said shock-responsive meansand operate the device.

15. A device as claimed in claim 14 wherein said shockresponsive meanshas two parts, and said manually controlled means includeselectromagnetically operated means engageable with at least one of saidparts to operate the device.

16. A device as claimed in claim 2 having means biasing said holdingmember, and means to adjust said biasing means for varying the responseof said holding to shock forces.

17. A device as claimed claim 2 wherein the flexible connection has adeviated portion acting on said holding member and wherein theshock-responsive means move under shock to alter said deviated portionand move said holding member, and means biasing said holding member, andmeans to adjust said. biasing means for varying the response of saidholding to shock forces.

18. A device as claimed in claim 3 wherein said weight masses areconical and tiltable about their base edge.

19. A device as claimed in claim 2 wherein the shock responsive meansincludes first and second weight masses, the first masses being aflixedto the opposite ends of said flexible connection, a second weight massbeing associated with each first weight mass and acting in concert withit to compensate for any ineffectiveness of the one of said first massesunder forces acting in certain directions, said second weight massesbeing located in recesses of the same shape as themselves in said base.

References Cited in the file of this patent UNITED STATES PATENTS1,777,665 Gibson Oct. 7, 1930 2,178,159 Battestin et a1 Oct. 3 1, 19392,783,321 Richardson Feb. 26, 1957 2,966,562 McElvain Dec. 27, 1960

1. IN A DEVICE RESPONSIVE TO PREDETERMINED SHOCK VALUES, A BASE RECESSEDTO RECEIVE FIXED AND MOVABLE PARTS OF THE DEVICE, A HOLDING MEMBERMOUNTED ON SAID BASE, MEANS BIASING SAID MEMBER INTO A CERTAIN POSITION,SHOCK RESPONSIVE MEANS INCLUDING A PLURALITY OF WEIGHT MASSES MOVABLE TOMOVE SAID HOLDING MEMBER FROM SAID CERTAIN POSITION IN RESPONSE TO APREDETERMINED SHOCK FORCE VALUE IRRESPECTIVE OF THE FORCE DIRECTION, ANDA FLEXIBLE CONNECTION BETWEEN SAID WEIGHT MASSES AND SAID HOLDING MEMBERFOR MOVING THE LATTER IN RESPONSE TO SAID PREDETERMINED SHOCK FORCEVALUE.